In recent years there has been a steady growth in the use of polymeric compositions as a substitute for wood and other materials of construction in building applications. Of particular significance has been the increased use of rigid polyvinyl chloride in place of wood for house sidings. This polymeric material has many decorative and structural attributes that are desired by many home owners. It can be blended with a wide variety of inorganic pigments to give an infinite number of colors and hues. Many of these pigments, such as the Meteor.RTM. colors produced by Harshaw/Filtrol Partnership are compatible with polyvinyl chloride and are especially formulated to be resistant to fading in sunlight.
Polyvinyl chloride compositions are blended with various additives to increase their tolerance to sunshine, particularly the rays in the infra red (700 to 1000 nm) range. Without these additives, a polymeric composition readily oxidizes and degrades, becoming brittle and cracking in a very short time. Also, when used as siding, the polymer tends to buckle and become unsightly in appearance.
One important characteristic of the pigments and other additives that are blended with the vinyl is their ability to reflect infra red rays. A highly reflective siding will remain cooler when exposed to sunlight than a siding containing additives which readily absorb many of these IR rays. Lower temperatures mean lower heat buildup within the structure and longer life for the siding. With the desire of customers to have extremely stable, maintenance free siding, manufacturers have been compelled to warrant the life of siding materials for 20 or 30 years. With this prolonged exposure, a reduction of a few degrees in heat build-up translates into a substantial increase in the life of the siding.